Time slot-controlling circuit for keyboard switch module, and ap

Details Time slot-controlling circuit for keyboard switch module, and ap Time slot-controlling circuit for keyboard switch module, and ap

1982-05-28

1984-12-18

Groody, James J.

Communications: electrical

Audible indication

Percussion-type sound producer

340365R, 340365S, 179 90K, 400485, G06F 302, H04M 126

Patent

active

044893108

ABSTRACT:
A time slot-controlling circuit (14, 14'), applicable for use with diverse types of keyboard-operated utilization devices or apparatus (18, 97, 98), such as in a pushbutton telephone (90), allows all (or pre-selected) keyboard-mounted key switches (24a-n, 24a'-h') to acquire a selected one of at least two different time slot-dependent operating states. This advantageously allows each key to initiate or control more than one work (or logic) function performed by an associated keyboard-operated utilization device or apparatus (18, 97, 98), as typically employed in a composite system or apparatus (10, 90). Such a two-state mode of operation is accomplished by each of two illustrative time slot-controlling circuit embodiments (14, 14') comprising a common time slot signal generator (21, 21'), which is responsively connected to a plurality of control signal generating channel selector circuits (22a-n, 22a'-h'). The signal generator (21, 21') includes an astable multivibrator (34, 34') coupled to a time slot controlling flip-flop (34). Each of the channel selector circuits (22a-n, 22a'-h') comprises a pair of gate-controlled flip-flops (64, 68), each of which is adapted to produce a key-initiated output control signal on only one of two output channels (e.g., A, or A.sub.2 to N.sub.1 or N.sub.2) thereof at any given time. On which channel such a control signal is produced is dependent on whether the associated key (24a-n) has been actuated during the first (T.sub.1) or second (T.sub.2) time slot switching state period established therefor. Either a separate time slot signal responsive visual indicator, such as an LED (53) mounted in each key, when of the pushbutton type, or a single LED common to all of keys, provides an indication (e.g., LED ON or OFF) of which time slot operable state each switch is in at any given time.

REFERENCES:
patent: 3274345 (1966-09-01), Ham
patent: 3956745 (1976-05-01), Ellis
patent: 4099246 (1978-07-01), Osborne
patent: 4352959 (1982-10-01), Warnecke
patent: 4454501 (1984-06-01), Butts

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